package com.xzz.mybatis.generator.utils;

import org.springframework.aop.framework.AdvisedSupport;
import org.springframework.aop.framework.AopProxy;
import org.springframework.aop.support.AopUtils;
import org.springframework.util.ReflectionUtils;

import java.lang.reflect.Field;

/**
 */
public final class MyAopTargetUtils {

    private MyAopTargetUtils(){}

    /**
     * 获取 目标对象
     * @param proxy 代理对象
     * @return
     * @throws Exception
     */
    public static Object getTarget(Object proxy) throws Exception {

        if(!AopUtils.isAopProxy(proxy)) {
            return proxy;//不是代理对象
        }

        Object tmpObj = null;
        if(AopUtils.isJdkDynamicProxy(proxy)) {
            tmpObj = getJdkDynamicProxyTargetObject(proxy);
        } else { //cglib
            tmpObj = getCglibProxyTargetObject(proxy);
        }

        return getTarget(tmpObj);
    }


    private static Object getCglibProxyTargetObject(Object proxy) throws Exception {
        Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0");
        ReflectionUtils.makeAccessible(h);
        Object dynamicAdvisedInterceptor = h.get(proxy);

        Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");
        ReflectionUtils.makeAccessible(advised);

        return ((AdvisedSupport)advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();
    }


    private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception {
        Field h = proxy.getClass().getSuperclass().getDeclaredField("h");
        ReflectionUtils.makeAccessible(h);
        AopProxy aopProxy = (AopProxy) h.get(proxy);

        Field advised = aopProxy.getClass().getDeclaredField("advised");
        ReflectionUtils.makeAccessible(advised);

        return ((AdvisedSupport)advised.get(aopProxy)).getTargetSource().getTarget();
    }
}
